Atomic Layer Deposition of TiO2 and TiN on cemented carbide

Sammanfattning

The hard coating industry is essential for modern technology; miniaturization of critical parts will increasingly require specialized tools with complex geometries. This in turn creates a demand for uniform and conformal hard coatings on geometrically complex surfaces. Atomic layer deposition (ALD) offers conformal, dense and precise thickness control of the deposited films but the research of hard coatings via ALD is scarce. In this study, TiO2 and TiN ALD processes were developed using the precursor TDMAT with H2O and NH3, for TiO2 and TiN respectively. The deposited films were characterized by XRD, SEM and XPS whereafter the processes were used to deposit TiO2 and TiN on cemented carbide cutting inserts separately. The TiO2 process produced stoichiometric TiO2 films that showed good coverage with anatase crystal structure after annealing. TiO2 was successfully deposited on cemented carbide ,showing good conformality, nice coverage and a rough surface. The TiN process was found to be more challenging during process development with hints that TDMAT is not a perfect ALD precursor. Longer pulse lengths of TDMAT resulted in more porous films and increased amount of nitrogen and carbon likely due to ligand incorporation. The process was successfully applied to cemented carbide with good conformality and coverage. These findings show that cemented carbide works as a substrate for ALD processes and further investigation into the use of TDMAT as an ALD precursor is warranted.